2,490 research outputs found
The ALICE muon spectrometer and related physics
ALICE, présenté par P. DupieuxThe LHC heavy ion physics program aims at investigating the properties of strongly interacting matter at extreme energy density where the formation of the Quark Gluon Plasma is expected. Among the most promising observables, open heavy flavours and heavy quarkonium states are especially relevant since, on the one hand, they are copiously produced and, on the other hand, they provide sensitive information on the collision at both short timescale (production mechanisms) and long timescale (medium effects). In ALICE, they will be measured through the hadronic channel as well as from (di)electrons and (di)muons. Particular emphasis will be put here on their measurement in the (di)muon decay channel. The ALICE muon spectrometer will be described as well as its construction and installation status. A few selected topics concerning muon physics in heavy ion collisions at LHC will be addressed and the expected performances of the ALICE muon spectrometer will be shown
Physics perspectives with the ALICE muon spectrometer
présenté par P. Dupieux, paru dans le supplément du journalALICE (A Large Ion Collider Experiment) will be the detector dedicated to the study of nucleus nucleus collisions at the LHC. The muon spectrometer of ALICE is dedicated to the measurement of heavy flavors in the muon channel. A brief description of the ALICE muon spectrometer and its physics program is reported. The expected performances for open and hidden charm and bottom measurements are presente
The Dimuon Trigger of the ALICE - LHC Experiment
We describe the trigger system of the ALICE dimuon spectrometer, based on RPC detectors. The background rate is at least one order of magnitude less in ALICE than in LHC p-p experiments due to the lower luminosity in ion running. Hence we study the possibility to operate the RPCs either in streamer or proportional mode. We report a study done with cosmic rays concerning gas mixtures for streamer mode. The aim is to minimise the streamer charge for a better flux capability of the RPC and a smaller cluster size, as needed for ALICE. We also give the results of a beam test at SPS where the RPC was placed in the vicinity of a hadron absorber, simulating the operation conditions in ALICE
The Local Trigger Electronics of the ALICE dimuon trigger
This document has been prepared for the Production Readiness Review of the Local trigger electronics of the ALICE dimuon arm, LHCC milestones n°429. It describes the design and the performances of a prototype board, developed at the LPC Clermont-Ferrand, in VME 9U format and based on programmable circuits
Abundance of Delta Resonances in 58Ni+58Ni Collisions between 1 and 2 AGeV
Charged pion spectra measured in 58Ni-58Ni collisions at 1.06, 1.45 and 1.93
AGeV are interpreted in terms of a thermal model including the decay of Delta
resonances. The transverse momentum spectra of pions are well reproduced by
adding the pions originating from the Delta-resonance decay to the component of
thermal pions, deduced from the high transverse momentum part of the pion
spectra. About 10 and 18% of the nucleons are excited to Delta states at
freeze-out for beam energies of 1 and 2 AGeV, respectively.Comment: 14 pages, LaTeX with 3 included figures; submitted to Physics Letters
Two-proton small-angle correlations in central heavy-ion collisions: a beam-energy and system-size dependent study
Small-angle correlations of pairs of protons emitted in central collisions of
Ca + Ca, Ru + Ru and Au + Au at beam energies from 400 to 1500 MeV per nucleon
are investigated with the FOPI detector system at SIS/GSI Darmstadt.
Dependences on system size and beam energy are presented which extend the
experimental data basis of pp correlations in the SIS energy range
substantially. The size of the proton-emitting source is estimated by comparing
the experimental data with the output of a final-state interaction model which
utilizes either static Gaussian sources or the one-body phase-space
distribution of protons provided by the BUU transport approach. The trends in
the experimental data, i.e. system-size and beam energy dependences, are well
reproduced by this hybrid model. However, the pp correlation function is found
rather insensitive to the stiffness of the equation of state entering the
transport model calculations.Comment: 9 pages, 8 figures, accepted at Eur. Phys. Journ.
Measurement of and mesons in Al+Al collisions at 1.9 GeV
New measurement of sub-threshold and production is
presented. The experimental data complete the measurement of strange particles
produced in Al+Al collisions at 1.9 GeV measured with the FOPI detector at
SIS/GSI. The / yield ratio is found to be and is in good agreement with the
UrQMD model prediction. These measurements provide information on in-medium
cross section of - fusion which is the dominant process on
sub-threshold production.Comment: 5 pages, 4 figures, accepted for publication in Phys. Rev.
Strange meson production in Al+Al collisions at 1.9A GeV
The production of K, K and (1020) mesons is studied in Al+Al
collisions at a beam energy of 1.9A GeV which is close or below the production
threshold in NN reactions. Inverse slopes, anisotropy parameters, and total
emission yields of K mesons are obtained. A comparison of the ratio of
kinetic energy distributions of K and K mesons to the HSD transport
model calculations suggests that the inclusion of the in-medium modifications
of kaon properties is necessary to reproduce the ratio. The inverse slope and
total yield of mesons are deduced. The contribution to K production
from meson decays is found to be [17 3 (stat) (syst)]
%. The results are in line with previous K and data obtained for
different colliding systems at similar incident beam energies.Comment: 16 pages, 11 figure
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